Apparatus for applying hot melt adhesive to carton blanks



J. A. ZINN, JR

Nov. 17, 1953 APPARATUS FOR APPLYING HOT MELT ADHESIVE TO CARTON BLANKS 6 Sheets-Sheet l Filed June 20, 1950 Ill IIIIIIT INKENTOR.

NOV. 17, 1953 L A ZINN, JR 2,659,340

APPARATUS FOR APPLYING HOT MELT ADHESIVE TO CARTON BLANKS Filed June 20, 1950 6 Sheets-Sheet 2 IN V EN TOR.

JuZuS A. Zz'fmjd:

APPARATUS FOR APPLYING HOT MELT ADHESIVE TO CARTON BLANKS Filed June 2o, 195o 6 sheets-sheet 3 'wil' wf; w w, E

M l N INVENToR. i Julius A. ZifzlLf/f.

` By @NM1 M1/1M t? darvzqgs AAe NOV. 17, 1953 A zlNN, JR 2,659,340

APPARATUS FOR APPLYING HOT MELT ADHESIVE TO CARTON BLANKS Filed June 20, 1950 6 Sheets-Shea?d 4 lll I www" INVENToR.

IJLLMLSA. Zzlzlz, J2'

NOV. 17, 1953 1 A, ZlNN, JR 2,659,340

APPARATUS FOR APPLYING HOT MELT ADHESIVE TO CARTON BLANKS Filed June 20, 1950 6 Sheets-Sheet 5 ffy@ H nu HMI i i ,MI5

lli

1| .MM I' NOV. 17, 1953 J, A ZlNN, JR 2,659,340

APPARATUS FOR APPLYING HOT MELT ADHESIVE TO CARTON BLANKS Filed June 20, 1950 6 Sheets-Sheet 6 INVENTOR.

Patented Nov. 17, 1953 OFFICE Arkana-rust FoRfAPPI-JYING; Huil?.v 1v1-ELT,

fro: 4cAR'roNI BLANKS .Itilius,A.,Zni1in, Jr., Chicago, I'll. sputum Juneau, 1950` serisiNo. 169,163

Y 2. Claims,` (c1. i-iszoz) present. invention relatesV tof methods and apparatus for applying;v hat melt.l adhesive to carton blanks.,` and, more.' particularly,. to: mathe odsl andapparatus for7 simultaneously' apply-ing.. such adhesives to.: both sides otazpaperboard carton blank.

Although not speciiicallyy limited; thereto, methodsf and' apparatus: embodying theA present invention are particularly; designed forl use with and willuhereinater illustrated and described in:- conneetion with carttm` blanks: of tliettyipe disclosedV aspriorf Patent-No. 2:4le2.6.66 issued December 17, 1946 to the presentziriventorf., Eurthermorewthe methods;- ar'id apparatus; of the present invention are particularly Suitable for use; in: the conveying and' feeding apparatusV of a carton. forming? machine," off the! type disclosed iny a. pniorfP-a'tentJ-No. 480.17m issued August 30, 1949iA tofJul-iuseA; Jr. and Michael J. Wilson. p

Such cartons:V are formed from' ypapeifboard blanks upon. botli sidesofwhich. there, has: been deposited aA pattern of .ther said. adhesiiefo the appropriata configuration toenablef the carton to. be sealed atter iiingf aniclosingf the same, and? which` isV p'art'ilziilarlly suitable,l for` use in the apparatus` for` v closingl and sealing cartons of the type disclosed in an UnitedStates patent application, Serial' No: 11561136, led- April 19, 1950,1byr Juliusli'.l Jr.` and Curtis B; Shaw. Inl order?` that` th'e'saiclirv blanks may beV47 in: a1 eon- -tiriuin'g! operation. immediat'iey formed-.1 int'oia carton, after-fthe# application of such adhesive totheblank withoutfwatirigfor the 'said adcommonly called ah photfrnelthadhesiveg ispre'fferablyl applied"` to the blankr in the; desired pattern; Frtherinore",` in' the event?" that* the-'said apparatus nereiiiafterto be' disclosed" for apply-L ing" than'. i nielt' nge-used. tjoj apply" the' :said not Ineltadli'esle'" 0f bllks `that' to` be'V 'stored for fiitilrefabrmation into cartons th'saiid ad'.- hesive applied"` blanks may bei immediately stzicliedione.Y on ton ofithefother a oiitiiiii-i-s operationwiti-iour experiencing. the danger of one adhesive applied lelariltfstaitikingfol the other;

In depositing adhesive on the blank, it desirablewtofanrlif, it; simultaneouslyto both sides oit-the blenkiineorder toprovde afcompaet structure.- lot' simple,-cons trnotionl as.v wellas to minimize thefoneralksizeiand oost; oithei'eqilipf meut..v While? certain arrangemnutsl heretofore proposedlhavefemploxedi-aepair of.; epposedfrolis, sautent.4 which,istlieatedy-toii2n1y-a-not meltfadf hesive, to one side of a blank, or web, at one time; when it isdesired to apply a hot` melt adhesive. simultaneously to both. sides of the blank, a. problem arises in connection with the upper roll, due to the tendency of' the liquidlike adhesive to ilovv out of the intagliojpattern of the upper roll under the inuence of gravity and thus to deposit adhesive in undesired areas of the blank.

Additionally, when heatedY rolls are used tojapply the adhesive, as is'. necessary in the case 0I a hot melt adhesive, the rolls tend to carbni'ze any organic material which may collectthereon and the resultant carbon particles produce'. peripheral scoring of the. surface of the rolls, and the consequent depositing of adhesive in un.- desired areas oftlieblanks.` n

Accordingly, it is an object of the present invention. to. provide methods oi and" apparatus for simultaneously applying, a ljotV meltY adhesive to bothesidesk of a paperboardV blank in a predetermined pattern;

It is. anotherA object. Qf.. the presenty invention to provide new' and'irnproved methods and apparatus for simultaneously applying a pattern of hot melt'A adhesiveto both sides of a paperboard blank Without depositing adhesive: undesired areas ofthe blank;

It is a further objeet-off thel present invention to provide new and iin-proved methods yand apparatus for simultaneously applying a' not melt adhesive to both sides o-f a paperboard, carton blank in which scoring of the suracefof the adhe'sive applicator' rolls and the resultant scoringandyor' depositing.-7 of adhesive undesired areasof theblank is minimized.

It is still another object; of; the present invention to provideyr` new and: improvedmethods and apparatus for simultaneously applying Va hot meltf adhesiveI tera-paperboard blank wherein an .upper applicator; roll; is; rotated at, a ratesuiiicient. to.: prevent liquid` adhesive from flow-v ing. onto. undesired: portions: of the uiuil-` appli# catorfroll.

Another object; of;4 theV present invention. resides in theprovision ofv mechanism for rotating a pair of opposed applicator rolls in` Oppositedirectionsvwhilje providing for adjustment. of the separation between the rolls.

Briefly,v in accordance with. one, aspect of Ythe invention,y the method of simultaneously applying. a predeterminedpattern of, hot. melt adhesive to. both sides Vofy apaperboard` blank cornprises the steps, ofsmultaneously removing loose organic material from both sides of the paperboard blank, depositing adhesive which is heated to a thin liquid state on a pair of heated opposed rolls having intaglio patterns of said predetermined configuration, removing the adhesive from the surface of the rolls, rotating the rolls at a rate suicient to hold the adhesive within the intaglio pattern on the upper roll, simultaneously transferring the adhesive on said rolls to both sides of said blank by passing said blank between the rolls at a rate equal to the peripheral rate of the rolls and synchronized therewith and partially solidifying the adhesive so transferred as it strikes the blank to pull the adhesive out of the intaglio patterns of the rolls,

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which:

Fig. 1 is a side elevational View of a preferred form of apparatus for carrying out an adhesive applying method embodying the present invention;

Fig. 2 is a plan View of the apparatus shown in Fig. 1;

Fig. 3 is a side elevational View of the apparatus of Fig. 1 taken from the opposite side thereof and including the driving mechanism therefor;

Fig. 4 is an end elevational View taken along the line 4-4 of Fig. 3;

Fig. 5 is a detail sectional View taken along the line 5--5 of Fig. 3;

Fig. 6 is a sectional view on a larger scale taken along the line 6-6 of Fig. 4;

Fig. 7 is a sectional view on a larger scale taken along the line 1-1 of Fig. 1;

Fig. 8 is a bottom view taken along the line 8-8 of Fig. 6;

Fig. 9 is a top view taken along the line 9--9 of Fig. 6;

Figs. 10 and 1l are enlarged fragmentary views showing adhesive patterns deposited on a paperboard blank in accordance with the method and apparatus of the invention;

Fig. 12 is a detailed sectional view taken along the line l2-l2 of Fig. 10;

Fig. 13 is a detailed sectional view taken along the line |3-I3 of Fig. 11;

Fig. 14 is a plan view of two opposed overlapping carton blanks illustrating the adhesive pattern which is simultaneously applied in accordance with the invention; and

Fig. 15 is a perspective view of a completed carton.

Referring now more particularly to the drawings, there is shown in Figs. 1 to 9, inclusive, an apparatus embodying the present invention for Simultaneously applying a hot melt adhesive to both sides of a series of spaced carton-blanks of the type shown in the Zinn Patent No. 2,412,665 referred to heretofore and also shown in Figs. 10 to l5 inclusive of the drawings.

While the adhesive which is applied by means of the apparatus of Fig. 1 and in accordance with the methods of the present invention may comprise any suitable thermoplastic adhesive ci the hot melt type which is a solid at normal temperatures and becomes a liquid at a predetermined elevated temperature, Ifprefer to employ a hot melt adhesive compounded in accordance with the following formula:

80 to 90% Polyamide resin 3 to 6% Phthalate plasticizer 6 to 10% Esterified hydrogenated rosin 1 to 3% Paraffln wax This adhesive may be purchased from the Union Paste Company, of Hyde Park, Massachusetts.

A hot melt adhesive compounded in accordance with the above formula has been found particularly suitable for use in sealing paperboard cartons of the above-described type. Such an adhesive, when heated to an elevated temperature,

becomes a thin fluid which is suitable for application to paperboard blanks in a predetermined pattern. However, if the temperature to which the adhesive is raised is considerably above the the melting point of the adhesive, the paraffin wax will evaporate in due course of time resulting in carbon particles being formed due to carbonization of the adhesive compound. These particles will tend to gather at the scraper edges and cause scoring of the peripheral surfaces oi' the rolls with the consequent scoring and/or depositing of adhesive in undesired areas of the paperboard blanks passing therethrough. Accordingly, the temperature of the hot melt adhesive is maintained at all times within a predetermined range which is great enough to melt the adhesive but which is not so great as to cause carbonizing thereof.

Considering now the apparatus shown in the drawings, this apparatus comprises an upper conveyor indicated generally at 2l which supplies carton blanks in the properly timed relation to a pair of opposed applicator rolls indicated generally at 22 and 23. The carton blanks to which the hot melt adhesive has been applied in the desired pattern by means of the rolls 22 and 23 are conveyed away on a lower discharge conveyor indicated generally at 24. The rolls 22 and 23, as best shown in Figs. 8 and 9, are provided on their respective surfaces with engraved portions 25 and 26 by means of which the adhesive in a thin liquid state is applied to the blanks in the desired patterns.

The conveyor mechanisms 2l and 24, as best shown in Figs. l and 2, comprise a pair of aligned inner rails 28 and 29 which extend up to the adhesive applying rolls 22 and 23, and a common outer rail 39 which extends across in front of the rolls and is adjustable inwardly and outwardly to accommodate carton blanks of various widths. The conveyor mechanism 2l includes an endless chain 32 which is disposed above the rails 28 and and is provided with outwardly extending fingers 33 which are adapted to engage the carton blanks and move them along the supporting rails. The discharge conveyor 24 is provided with asimilar endless chain 34 which is disposed below the rails 29 and 30 and is provided with the carton engaging fingers 35.

In order to move the fingers 33 and 35 in the proper timed relationship with respect to rotation of the applicator rolls 22 and 23J the roller chains 32 and 34 are respectively provided with sprocket Wheels 36 and 31 secured on the shafts 38 and 39 which are driven from a main drive shaft 40 through a main conveyor drive sprocket 4| positioned on the shaft 40. Thus, the sprocket 4| is connected through a chain 42 to a sprocket 43 on the shaft 38 and the shaft 38 `is further provided with a sprocket 4I which is connected aia-tasso through the chain 45 to a sprocket 46 on the shaft 39. As the main drive shaft 40 is rotated, the sprocket wheels 36 and 31 are 'driven in the properly timed relation to present lcarton blanks to the applicator rolls 22 and 23 in the proper relationship with respect to the engraved patterns on the surfaces thereof.

y In order to clean the surfaces rof fthe carton blank, so that loose 'organic material thereon will not collect upon the heated applicator rolls 22 and `23 and carbonize thereon and produce scoring of the carton blanks on the surface of 'the rolls there is provided at a point along the upper conveyor 2| a cleaning and suction appa- -r'atus whereby such loose inorganic material is removed. Thus, there is provided a pair of revolving brushes 41 which are 4positioned above and below the carton blanks moving along the rails 28 and 30, the brushes 41 engaging both surfaces of the carton blank. The brushes 41 provide a sweeping action on both surfaces of the blank and raise the nap, or fur, which is produced on these blanks by the original paperboard cutting operation. Positioned along the conveyor 2| at a point after the brushes 41, there is provided a pair of suction heads 48 and '49 which are again positioned above and below the carton blank as it is moved along the rails 28 and 30. The suction heads 48 and 49 are supplied from a suitable vacuum apparatus (not shown) and the vacuum pressure of each head is substantially equal so that the blank will remain properly positioned on the rails 28 and 30. The suction heads 48 and 49 operate to remove any loose material which has been raised by the brushes 41 and which has not been brushed olf prior to passage of the blanks between the suction heads. With this arrangement, loose organic material does not reach the applicator rolls 22 and 23' and the production of carbon particles which would cause scoring of the carton blanks and the surface of the rolls is prevented. In this connection it will be understood that other types of cleaning apparatus, such as, for example, electrostatic precipitator apparatus or the like, may equally Well be employed to `remove lloose carbonio material from the blanks.

In order to support the hot melt adhesive applicator rolls and driving mechanism therefor, there is provided, as is best shown in Figs. 3 and 4, a generally C-shaped supporting structure which comprises a base portion 58 which is lsupported for sidewise movement, so as to ladjust the position of the rolls with respect to the rails 28, 29, and 3D by means of the flange portion which rides within grooves formed in suitable side supports 52. The base portion '50 -supports a post 55 at the top of which there is supported a cross arm 55. The upright post 55 'supports a driving motor 51 which is connectled through the belt 58 to a gear reduction mechanism 59. The mechanism 59 is provided with a sprocket wheel 68 and a chain i6| connects the vsprocket 60 to a main sprocket Wheel 62 on the main drive shaft 40. Y

In order to drive the applicator rolls 22 and '23 in properly timed relationship with respect to the yconveyors 2| land 24, which conveyors are driven from the drive shaft 48 in the manner described heretofore, the lmain drive shaft 40, which supports the applicator roll 22 at one end thereof, is provided with a driving gear 65 which meshes with a pair of idler gears 56 and 61 supported on suitable shafts vjournalled in the supporting post 55. The idler gear I|i`| meshes 6 with adrlven gear l'8'8 positioned on a lower drive shaft '59 journalled in the supporting post 55 and supporting at its other end the applicator roll 23.

Referring now more particularly 'to Figs. '6 and y'I wherein the applicator rolls and the 'manner in`which these rolls are supported `in the above-described supporting structure are shown in more detail, vthe upper applicator roll 22 'comprises an outer -cylindrical shell 1D on the outer surface of which there is engraved 'or A"otherwise formed the vdesired pattern 25 in which the adhesive is to be deposited. Within the Vlcylindricalvm'ember 10 there is -positioned an electrical heating element 12 encased in an insulating'material 13. yThe outer cylindrical shell 10 Vis supported by means of a flanged hub 14 and a side Wall member 15. In order to confine the heat produced by the element 12 to the -outer shell 10, a pair of thel'side disks 16 and 77 and an inner supporting hub 18 formed of insulating material are provided. The above-described a'ssembly is held together by means rof the bolts 19 which pass through the side wall member 15 and the insulating members 16, V11, and 18 and thread into the flange of the hub 14. The flanged hub 14 is supported on the main drive shaft 40 and is positioned between the sleeve bearings 8|] and 8|. The bearings 80 yand 8| are in turn supported by the side vsupports 82 and 83 which are secured to tile under 'surface of the vcross arm 56 and depend therefrom. The flanged hu'b 14 is keyed to the drive shaft v4l) by means of the Woodruff keys 84 whichare positioned within the grooves 85 in the hub A14, so that the applicator roll 22 is directly driven 'from the main drive shaft 40.

In order to supply electrical power to the heating element 12 while permitting the drive shaft to rotate, and to the end that the applicator rolls and the heating elements may be separately removable lso that applicator rolls having different engraved patterns on the surface thereof may be readily substituted, the rolls are constructed internally in the manner shown in Fig.

1 in connection with the bottom applicator roll 23. In this connection, it will be understood that the roll 23 is identical in construction to the above-described roll 22, and, hence, any discussion of one of the applicator rolls applies equally Well to the other.

In order to connect the heating element 1'2 to an external source of power, the terminals 'thereof are connected to a pair of spring contact .members and 9 I. The free ends of the conductive members and y9| press again the heads of conductive studs 92 and 93. which are supported in blocks of insulating material 94 and 95 posi'- tioned on opposite sides of the flanged hub 14. The conductive Vstuc'l'ii is arranged to make contact with a central conductive rod 98 through a contact member 91 which engages one end ofthe rod 96. The rod 96 is encased in an insulating shell 98 'which is 'in turn surrounded by a conductive sleeve 98 which is connected 'through a contact member |60 engaging the inner end thereof to the conductive 'stud 93. The sleeve `v9'9 is insulated from the drive 'shaft by `means 'off'an outer insulating shell lill. The ic'onductive sleeve 99 is provided with a flanged end portion '|02 against which the end of a wiper arm |03 may make contact as the drive shaft is rotated. -Like- "wise, the end of another wiper `arm '|04 makes electrical contact with the 'exposed end of the `central conductive 'rod 38 as the drive shaft rotates. The wiper arms |03 and |04 are supported in an insulated block |05 and are connected through the conductors |00 and |01 to a suitable source of current. The contact members 91 and |00 are provided with conical seats which are adapted to receive the end portions of the conductive studs 92 and 93 when the applicator roll assembly is slid onto the drive shaft to the correct position so as to permit engagement therewith. In this connection it will be understood that the applicator roll assembly is keyed to the drive shaft so as to permit insertion thereon in one position only so that the applicator roll assembly may be slid onto the drive shaft until the conductive studs make Contact with the respective contact members carried by the drive shaft at which time the assembly may be secured on the shaft by means of the collars |08 and |09. It will further be understood that electrical connection from the conductors ||0 and which may be supplied by the same source of power as the conductors |06 and |01, is made to the heating element of the upper applicator roll in a manner entirely similar to that discussed in connection with the lower applicator roll 23.

The brackets 82 and 83, which support the end of the drive shaft 40, also provide a support for a triangular shaped adhesive container |20, one side of which is closed by the surface of the roll 22. In order to maintain the hot melt adhesive in a thin liquid state, the sloping 1bottom wall |2| of the adhesive container is adapted to be heated by a suitable electrical heating unit |22 which is encased in insulating material and is placed in contiguity with the bottom surface of the Wall |2|. At its lower edge the wall 42| of the container is provided with a scraper |23, one edge of which is constantly in engagement with the surface of the roll 22 so as to remove adhesive from all portions of the roller surface except the pattern. In order to adjust the adhesive container |20 to provide a scraping rit with the roll 22, suitable supporting pins |24 are positioned within slots |25 in the side wall so as to permit horizontal movement of the container. The bottom applicator roll 23 is also provided with an adhesive container having a sloping bottom wall |3| which is heated by means of the electrical heating unit |32 in a manner similar to the container |20. The adhesive container |30 is further provided with a scraper |33, one edge of which is constantly in engagement with the surface of the roll 23 so as to remove the adhesive from all portions of the roll surface eX- cept the engraved pattern therein. In order that the adhesive may be maintained in a thin liquid state, the scraper |33 is provided with a tubular electrical heating unit |34, so as to maintain the scraping edge at the proper temperature. For the purpose of removing excess adhesive from the rolls after contact with the carton blank, and stripping the blank from the rolls in the event that the blank adheres to either roll, there is provided a pair of stripper and scraper blades and |4| which contact the surface of the rolls 22 and 23 immediately following the point of contact with the carton blank and which are biased against the surface of the rolls by means of the coil springs |42 and |43.

In order to provide for adjustment of the bottom roll 23 toward and away from the upper roll so as to insure proper engagement with the carton blanks and to permit the use of blanks of varying thicknesses, the drive shaft 69, on which the roll 23 is mounted, is journalled in a carriage Si comprising the side walls |45 and |46. The side walls |45 and |40 are provided at one end thereof with outwardly extending studs |41 and |43 (Fig. 9) which are adapted to be supported in suitable notches |50 (Fig. 6) in a pair of side brackets |5| and |52. The side brackets |5| and |52 are supported on a cross member |53 (Fig. 7) which is in turn supported from the upstanding post 55. At their opposite ends the side members |45 and |40 of the roll supporting carriage are connected to a pivoted block |55, which is adapted to receive the upper end of a pivotally mounted adjusting screw |56, the lower end of the screw |56 being threaded through a pivoted block |51 which is in turn supported from the cross member |53. With this arrangement, adjustment of the screw |56 is effective to raise and lower the roll |23 with respect to the roll 22.

In order to drive the adhesive applying rolls in predetermined relation with respect to the conveyor mechanisms 2| and 24 while simultaneously adjusting the separation between the rolls, as above described, and the movement of the conveyor mechanisms, the driven end of the drive shaft ES is mounted in a second carriage coinprising a pair cf arms |60 and iEI (Fig. '7) which are adapted to pivot about a point in alignment with the pivot pins |41 and |48 on the roll supporting carriage and also in alignment with the of the idler gear 61. To this end the arms |50 and itl are pivoted on the shaft @Sla which supports the idler gear G1, the shaft 89a being in alie .with the pivot pins |41 and |43 of port carriage.

In order to permit the l and 56| to be adjusted to coincide with the position of the lower applicator roll, We is provided, as clearly shown in Fig. 4, a l adjustment screw |52 which threads through a irst pivoted block |63 and supports en the upper end thereof a second block |64 which is pivotally supported between the side arms |53 and |62 at the other end thereof. With the above-described arrangement in which the roll supporting carriage is pivoted about a point which is in alignment with the axis of the idler gear 51, when the lower roll 23 is adjusted either toward or away from the upper roll, the shaft 03 and the gear 58 thereon move around. the idler gear E1 so as to maintain these gears in mesh although the separation between the rolls may be varied considerably. In this connection, it will be understood. that the wiper Contact arms |U3 and |04 associated with the lower applicator roll may be positioned so as to permit substantial up and down movement of the roll 23 while maintaining contact with the ends of the conductive members 9S and 59.

Considering now the operation of the abovedescribed hot melt adhesive applying apparatus, it will be understood that a suitable hot melt adhesive, preferably an adhesive compounded in accordance with the foregoing formula, is placed within the adhesive containers |23 and |30 and is melted by means of the heating units |22 and |32 to a suitable thin liquid state. As the applicator rolls 22 and 23 move through their respective adhesive containers, the adhesive is deposited on the surface thereof and the scraper members |93 and |33 operate to remove the adhesive from all portions of the roll surface except the engraved patterns 25 and 25. rEhe carton blank 20, both sides of which have been cleaned by means of the cleaning apparatus discussed in connection with Fig. l, passes between the applicator rolls 22 and 23 so as to deposit on both sides thereof thev adhesive, which is positioned within the engraved pattern of either roller. In this connection,l it will be understood that the separation between the rolls 22 and 23 may be adjusted by means of the adjusting screws |56 and |62 so as to provide the necessary pressure to facilitate transfer of the adhesive in the engraved indentations in the surface oi the` rollerY to the surface of the carton blank.

The carton blanks are preferably at room temperature or below, whereas the hot melt adhesive is at a suitably elevated temperature suchthat it is in a thin liquid state. It will be understood, in this connection.. that the adhesive containers, the applicator rolls, and the scraper members are all heated to the correct temperaturev and are thermostatically controlled` so as to maintain the adhesive in a thin liquid state. When the blank, which is relatively cool, passes between the heated rolls, the adhesive which strikes the surface of the blank on either side thereof, is partially congealed so as to pull the remaining adhesive out of the pockets, or engraved indentations, in the surface of the rolls. With this arrangement, a substantial amount of liquid adhesive is deposited in the desired areas of the blank although the indentations are relatively shallow and provide only a thin film of adhesive to work with. It will be understood that if the carton blank were heated to an elevated temperature, the adhesive would not congeal upon striking the surface thereof and hence little, if any, adhesive would be deposited in the desired areas on the blank.

In considering the action of the upper applicator roll 22 when a liquid-like adhesive is deposited within the engraved indentations thereon, it will -be seen that the adhesive due to the force of gravity, tends to flow out of the indentations during travel from the bottom edge of the adhesive container |20 to the point of Contact with the carton blank. However, I have found that the adhesive may be maintained in the desired pattern within these indentations by rotating the upper applicator roll at a speed which is suiiicient to prevent the liquid adhesive from owing out of the indentations and producing a blurred and non-distinct pattern on the carton blank. In this connection, it will be understood that the applicator rolls 22 and 23 are both driven at the same speed, hence, the applicator roll 23 is also l driven at the correct speed to keep the adhesive within the indentations on the upper roll. The distance from the bottom edge of the adhesive container |20 to the point of contact with the container blank is so related with the speed of rotation of the upper roll that the adhesive is held within the indentations thereof and a clear, distinct pattern of adhesive is deposited on the blank.

While the pattern may be of any desired configuration, it is preferred to provide the indentations thereof with the configuration, shown in Figs. l and l1, wherein the adhesive coating, deposited on the blank 2li by means of the methods and apparatus heretofore described is shown in detail. As shown, the adhesive pattern in Fig. comprises a plurality of horizontal lines of adhesive |80 which are crisscrossed with vertical lines I 8| of substantially the same width. In the alternative, the pattern shown in Fig. 1l may be employed wherein the pattern consists of a plurality of cup-shaped indentations |85 which are aranged in spiral lines within the areas which are to be covered. In either of the patterns shown in Figs. 10 and 11, the indentations are l0 preferably such that the adhesive is. maintained within, individual, or discrete cup-like indentations, which are substantially separated from the surrounding surface ofv the roll so that theJ adhesive is. maintained within the indentations during the travel from the bottom or" the upperadhesive container to the point of contact with they carton blank.

In Fig. 14 there is shown the adhesive pattern which is. applied to both sides of the carton blank 2|). As shown, one side of the carton 2.0 isl coated in the pattern indicated at |81 and the other side of the carton is coated as shown at |88. The carton blank, on which has been deposited the hot melt adhesive in the patterns shown at |81 and |88, is formed into a rectangular shaped body portion I 89 (Fig. 15) in which the bottom walls are folded and sealed to provide a liquid-tight seal. The open-mouthed container thus formed is then lled, closed and sealed by suitable apparatus so as to provide a bellows type end closure having an upstanding transverse closure rib. Preferably, the bellows type end closure may be formed and sealed by means of the apparatus shown in a co-pending application to Julius A. Zinn, Jr. and Curtis B. Shaw, Serial No. 156,736, which was filed on April 19, 1950.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modications may be made therein which are within the true spirit and scope of the invention as defined in the appended claims.

What is claimed as new and is desired to be secured by Letters Patent of the United States is:

l. Apparatus for simultaneously applying a predetermined pattern of hot melt adhesive to both sides of a paperboard carton blank, comprising a pair of heated intaglio rolls, means for depositing a thin nlm of adhesive which is heated to a thin liquid state on said rolls, means for removing substantially all of the adhesive from the surface of said rolls, means for rotating said rolls in opposite directions at a rate suflicient to hold the adhesive within the intaglio pattern of the upper roll, conveyor means for passing a carton blank between said rolls in predetermined relation to the intaglio patterns thereof to transfer simultaneously the adhesive thereon to predetermined areas on both sides of said blank, said blank being cooler than said rolls to congeal the adhesive so transferred as it strikes the blank and to pull the adhesive away from the intaglio patterns of the rolls, and means for simultaneously adjusting the separation between said rolls and the movement of said conveyor means while maintaining said predetermined relation between said rolls and said carton blank.

2. Apparatus for simultaneously applying a predetermined pattern of hot melt adhesive to both sides of a paperboard blank, comprising a pair of heated intaglio rolls positioned one above the other, means for depositing a thin film of adhesive which is heated to a thin liquid state on said rolls, means for removing substantially all of the adhesive from the unengraved surface of said rolls, means for rotating said rolls in opposite directions at a rate sufficient to hold the adhesive within the intaglio pattern of the upper roll after the surface thereof has been cleaned by said adhesive removing means and until said upper roll engages the upper surface of the blank, conveyor means for passing a carton blank horizontally between said rolls in predetermined relation to the intaglio pattern thereof,

thereby simultaneously to transfer the adhesive within the intaglio pattern of the rolls to predetermined areas on both sides of the blank, said blank being cooler than said rolls to congeal the adhesive so transferred as it strikes the blank and to pull the adhesive away from the intaglio patterns of the rolls, and means for smultaneously adjusting the separation between said rolls and the movement of said conveyor means while maintaining said predetermined relation between said rolls and said carton blank.

JULIUS A. ZINN, JR.

2 References Cited in the le of this patent UNITED STATES PATENTS Number Number Name Date Owens June 2, 1925 Murphy Nov. 20, 1934 Codwise May 31, 1938 Massey Jan. 2, 1940 Massey May 25, 1941 Pearson Sept. 1, 1942 Schleicher Jan. 25, 1944 Fluckinger Oct. 10, 1944 Lyons et a1 Apr. 26, 1949 FOREIGN PATENTS Country Date Great Britain Dec. 18, 1913 Great Britain Sept. 13, 1940 

